[zeromq-dev] using majordomo broker with asynchronous clients

[André Caron]

Throughput is bound by multiple factors.  In your case, my guess is that
your bottleneck is the throughput of a single TCP socket on your system.  I
doubt that you can reach millions of messages per second with only 3
clients.  If you add more clients, you should see the server's throughput
increase well over 30k.

Cheers,

André

On Thu, Dec 11, 2014 at 4:40 AM, Vishal Ahuja <vahuja4 at gmail.com> wrote:

> I removed the printfs, and increased the TCP send and receive buffers to
> the max possible. When I have two clients (running in parallel) sending
> 100k messages, there is no packet loss. But when I increase the number of
> clients to three, then each client receives around 93k packets. Also, the
> majordomo specification (http://rfc.zeromq.org/spec:7) says that the
> broker should be able to switch millions of messages per second, whereas I
> seeing a throughput of around 30k messages per second. Can someone tell how
> to improve the throughput?
>
> Sincerely,
>
> Vishal
>
> On Thu, Dec 11, 2014 at 10:37 AM, Andre Caron <andre.l.caron at gmail.com>
> wrote:
>
>> The broker uses a router socket, which silently drops outbound messages
>> when the sndhwm is reached.  If your client is reading more slowly than the
>> broker is writing, you'll lose messages.
>>
>> In your case, the slow part is writing to the terminal.  Try removing the
>> printf in the recv loop and you should lose fewer messages.
>>
>> André
>>
>> > On Dec 10, 2014, at 9:40 PM, Vishal Ahuja <vahuja4 at gmail.com> wrote:
>> >
>> > While reading the zeromq guide, I came across client code (pertaining
>> to the majordomo pattern) which sends 100k requests in a loop, and then
>> receives the reply in a second loop.
>> >
>> >     #include "../include/mdp.h"
>> >     #include <time.h>
>> >
>> >
>> >     int main (int argc, char *argv [])
>> >     {
>> >         int verbose = (argc > 1 && streq (argv [1], "-v"));
>> >         mdp_client_t *session = mdp_client_new ("tcp://localhost:5555",
>> verbose);
>> >         int count;
>> >         for (count = 0; count < 100000; count++) {
>> >             zmsg_t *request = zmsg_new ();
>> >             zmsg_pushstr (request, "Hello world");
>> >             mdp_client_send (session, "echo", &request);
>> >         }
>> >         printf("sent all\n");
>> >
>> >         for (count = 0; count < 100000; count++) {
>> >             zmsg_t *reply = mdp_client_recv (session,NULL,NULL);
>> >             if (reply)
>> >                 zmsg_destroy (&reply);
>> >             else
>> >                 break;              //  Interrupted by Ctrl-C
>> >             printf("reply received:%d\n", count);
>> >         }
>> >         printf ("%d replies received\n", count);
>> >         mdp_client_destroy (&session);
>> >         return 0;
>> >     }
>> >
>> > I have added a counter to count the number of replies that the worker
>> (test_worker.c) sends to the broker, and another counter in mdp_broker.c to
>> count the number of replies the broker sends to a client. Both of these
>> count up to 100k, but the client is receiving only around 37k replies.
>> >
>> > If the number of client requests is set to around 40k, then it receives
>> all the replies. Can someone please tell me why packets are lost when the
>> client sends more than 40k asynchronous requests?
>> >
>> > I tried setting the HWM to 100k for the broker socket, but the problem
>> persists:
>> >
>> >     static broker_t *
>> >     s_broker_new (int verbose)
>> >     {
>> >         broker_t *self = (broker_t *) zmalloc (sizeof (broker_t));
>> >         int64_t hwm = 100000;
>> >         //  Initialize broker state
>> >         self->ctx = zctx_new ();
>> >         self->socket = zsocket_new (self->ctx, ZMQ_ROUTER);
>> >         zmq_setsockopt(self->socket, ZMQ_SNDHWM, &hwm, sizeof(hwm));
>> >
>> >         zmq_setsockopt(self->socket, ZMQ_RCVHWM, &hwm, sizeof(hwm));
>> >         self->verbose = verbose;
>> >         self->services = zhash_new ();
>> >         self->workers = zhash_new ();
>> >         self->waiting = zlist_new ();
>> >         self->heartbeat_at = zclock_time () + HEARTBEAT_INTERVAL;
>> >         return self;
>> > }
>> >
>> > Vishal
>> > _______________________________________________
>> > zeromq-dev mailing list
>> > zeromq-dev at lists.zeromq.org
>> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> _______________________________________________
>> zeromq-dev mailing list
>> zeromq-dev at lists.zeromq.org
>> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>>
>
>
> _______________________________________________
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.zeromq.org/pipermail/zeromq-dev/attachments/20141211/3de49db1/attachment.htm>